Campbell Biology: Population Ecology and the Distribution of Organisms

Vocabulary flashcards covering ecological hierarchy, global climate, biomes, aquatic zonation, and population dynamics from Campbell Biology in Focus, Chapter 40.

Climate

The long-term prevailing weather conditions in a given area, primarily constituted by temperature, precipitation, sunlight, and wind.

Abiotic Factors

The nonliving chemical and physical attributes of the environment, including temperature, water, salinity, sunlight, and soil composition.

Biotic Factors

The living organisms that constitute the biological component of an ecosystem, including predators, competitors, parasites, and mutualists.

Macroclimate

Climate patterns operating on global, regional, and landscape scales.

Biome

A major life zone characterized either by dominant vegetation type (terrestrial biomes) or by physical and chemical environment (aquatic biomes).

Ecotone

The transition zone or area of intergradation between two adjacent terrestrial biomes, which may be wide or narrow.

Disturbance

A natural or human-caused event that changes an ecological community by removing organisms and altering resource availability, such as fire or storms.

Rain Shadow

A dry region formed on the leeward side of a mountain range where descending air warms and absorbs moisture, after air on the windward side rose, cooled, and released precipitation.

Tropical Forest

A biome found in equatorial and subequatorial regions with high temperature and humidity year-round, pronounced vertical vegetation layering, and high species diversity.

Savanna

An equatorial and subequatorial biome characterized by warm temperatures, seasonal precipitation, and a ground cover of grasses and forbs adapted to drought and fire.

Desert

A biome located typically in bands near $30^\bot\text{ N}$ and $30^\bot\text{ S}$ latitude and continental interiors, marked by low and variable precipitation (generally less than $30\text{ cm}$ annually).

Chaparral

A midlatitude coastal biome characterized by mild, rainy winters and hot, dry summers, dominated by drought- and fire-adapted shrubs and small trees.

Temperate Grassland

A midlatitude interior biome characterized by cold, dry winters and hot, wet summers, with fertile soils dominated by drought- and fire-adapted grasses and forbs.

Northern Coniferous Forest (Taiga)

The largest terrestrial biome on Earth, spanning northern North America and Eurasia, characterized by long, cold winters, precipitation of $30\text{--}70\text{ cm}$, and dominance by cone-bearing gymnosperms.

Temperate Broadleaf Forest

A midlatitude biome with hot, humid summers, cool winters averaging $0^\bot\text{C}$, and significant precipitation across all seasons, dominated in the Northern Hemisphere by deciduous trees.

Tundra

An expansive biome in the Arctic and high mountaintops (alpine) with low temperatures, herbaceous vegetation (mosses, grasses, dwarf shrubs), and short growing seasons.

Permafrost

A permanently frozen layer of soil found in the Arctic tundra that restricts the downward growth of plant roots.

Photic Zone

The shallow upper aquatic stratum into which sufficient sunlight penetrates to support photosynthesis.

Aphotic Zone

The lower aquatic layer that receives little to no sunlight, where net photosynthesis cannot occur.

Benthic Zone

The sediment-covered bottom substrate of an aquatic biome, populated by benthic organisms.

Littoral Zone

The shallow, well-lit, nearshore waters of a lake where rooted and floating aquatic plants can survive.

Limnetic Zone

The well-lit, open surface water of a lake situated away from the shore, where the water is too deep to support rooted vegetation.

Thermocline

A narrow vertical layer of rapid temperature transition in oceans and lakes that separates a warm, low-density upper layer from colder, denser deep water.

Oligotrophic Lake

A nutrient-poor, oxygen-rich body of water that is typically proportionately deeper with a lower surface-area-to-depth ratio.

Eutrophic Lake

A nutrient-rich body of water that has a high surface-area-to-depth ratio and frequently experiences oxygen depletion, especially when covered with ice.

Wetland

A productive habitat that is inundated with water periodically or permanently, supporting plants adapted to water-saturated, anaerobic soils.

Estuary

A coastal transition zone between a river and the sea, where salinity fluctuates with the rise and fall of the tides.

Pelagic Zone

The open-water biome of oceans and lakes comprising the photic and aphotic zones, constantly mixed by wind-driven currents.

Dispersal

The movement of individuals away from high-density population centers or from their parental origin.

Population

A group of individuals of the same species living in the same general area, delimited by boundaries and characterized by size and density.

Population Density

The number of individuals of a single species per unit area or volume.

Dispersion

The pattern of spacing among individuals within the geographic boundaries of a population, categorized as clumped, uniform, or random.

Territoriality

The behavioral defense of a bounded physical space against conspecifics, which typically leads to a uniform dispersion pattern.

Demography

The quantitative study of the vital statistics of a population, particularly birth rates and death rates, and how they change over time.

Life Table

An age-specific summary of the survival pattern and mortality rates of a population, constructed by tracking a cohort.

Cohort

A group of individuals of the same age followed from birth until death in a demographic study.

Survivorship Curve

A plot of the proportion or numbers in a cohort still alive at each age, graphically representing data from a life table.

Type I Survivorship Curve

A survivorship curve characterized by low death rates during early and middle life, followed by a steep increase in mortality in older age intervals.

Type II Survivorship Curve

A survivorship curve showing a constant mortality rate across all life stages of an organism.

Type III Survivorship Curve

A survivorship curve characterized by high juvenile mortality rates, with low death rates for the few individuals that survive to adulthood.

Reproductive Table

An age-specific summary of the reproductive rates in a population, typically measured by counting the female offspring produced by females in each age class.

Zero Population Growth (ZPG)

The demographic balance that occurs when per capita birth rate equals per capita death rate, resulting in a per capita rate of increase of $r = 0$.

Exponential Population Growth

Unrestricted population increase under ideal conditions described by $\frac{dN}{dt} = r_{\max}N$, generating a $J$-shaped curve over time.

Carrying Capacity ($K$)

The maximum population size of a species that a given environment can sustain indefinitely based on limiting abiotic and biotic resources.

Logistic Population Growth Model

A growth model where the per capita rate of increase declines as carrying capacity ($K$) is reached, described by $\frac{dN}{dt} = r_{\max}N\frac{(K - N)}{K}$ and producing an $S$-shaped curve.

K-selection

Density-dependent selection for life history traits that are advantageous and sensitive to crowding at high population densities near carrying capacity.

r-selection

Density-independent selection for life history traits that maximize reproductive output and success in low-density or uncrowded environments.

Metapopulation

A network of distinct local populations inhabiting fragmented patches of suitable habitat that are linked to one another by immigration and emigration.